<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>绝对定位</title>
    <style>
        div{
            width: 200px;
            height: 200px;
            background-color: blue;
            position: absolute;
            top: 200px;
            right: 0px;
        }
    </style>
</head>
<body>
    <!-- 没有父级元素或者父级元素没有定位的情况下 会以浏览器为界-->
    <div></div>
</body>
</html>